In recent years, with an increase in demand for energy savings in image formation with electrophotographic apparatuses, reductions in fixing temperatures of toners have been tackled. As examples of a method for improving low-temperature fixability, techniques for using crystalline polyester resins having sharp melting properties in which their viscosities decrease at temperatures higher than their melting points have been reported (PTLs 1 to 3).
As other examples of a method for improving low-temperature fixability, reductions in fixing temperatures by the use of resins having low glass transition temperatures have been reported. Toners each containing an ethylene-vinyl acetate copolymer serving as a resin having a low glass transition temperature have been reported (PTLs 4 to 8).
As a method for producing a toner, an emulsion aggregation method has been receiving attention from the viewpoint of easily controlling the particle size distribution, the particle size, and the form of a toner. The emulsion aggregation method is a method for producing toner particles, the method including an emulsification step of preparing a dispersion of resin microparticles in an aqueous medium, an aggregation step of aggregating the resin microparticles to form aggregated particles, a coalescence step of heating the aggregated particles and allowing the aggregated particles to coalesce, and filtration and washing steps (PTLs 9 and 10).